Guillermo del Toro's "Pacific Rim" is not just a green screen and post-production action flick (we're looking at you, "Transformers") -- though there is most definitely some of that. Filming was a far more analog, physical process than one might expect given the scale of the potential summer blockbuster.

The resulting fight scenes look incredible.

"The action in the movie is what you would have dreamt to see when you were 11," says director/writer/producer Guillermo del Toro in a new behind-the-scenes trailer.

Del Toro built entire four-story "robot helmet" sets/"cockpits" that would vibrate, shake and drop 15 feet to make the action look and feel real. With the hydraulic resistance and heavy water sprays, del Toro says he invented a "torture machine" for his heroes.

"The actors were in for a ride," he says. "It was like a little amusement park simulator."